我写了这个简单的Restful网络服务，并得到一个空白的回复。 为什么？

Question

I am learning to write a Restful webservice in PHP. So I followed a video tutorial and wrote the following basic webservice. The problem is that when I tried to access the web service via http://localhost/Test8/?name=c (because my index.php is located in Test8 directory) URL, I get a blank page .

But when the tutor in the video accessed it using http://localhost/rest/?name=c (because their index.php located in rest directory), they got {"status":200, "status_message":"Book found", "data":348} in the webpage.

What did I miss?

index.php:

<?php

//Process client's request (via URL)
header("Content-Type:application/json");

if (  !empty($GET['name'])  ) {
    $name = $GET['name'];
    $price = get_price($name);

    if (empty($price)) {
        //Book not found
        deliver_response(200, 'Book not found!', NULL);
    } else {
        //Send the response with book price
        deliver_response(200, 'Book found', $price);
    }

} else {
    //throw invalid request
    deliver_response(400, "Invalid Request", NULL);
}



 //API Functions
 function get_price($bookRequested) {
     $books = array(
        'Java' => 999,
        'C' => 348,
        'PHP' =>500
     );

     foreach ($books as $book=>$price) {
         if ($book == $bookRequested) {
             return $price;
         }
     }
 }


 function deliver_response($status, $status_message, $data) {
     header("HTTP/1.1 $status $status_message");

     $response['status'] = $status;
     $response['status_message'] = $status_message;
     $response['data'] = $data;

     $json_response = json_encode($response);
 }

?>

---

EDIT:

Just checked the console. It says Failed to load resource: the server responded with a status of 400 (Invalid Request) ...

I changed

if (  !empty($GET['name'])  ) {
    ...

} else {
    //throw invalid request
    ...
}

to

if (  !empty($GET['name'])  ) {
    echo '$GET["name"] is NOT empty';

    ...

} else {
    echo '$GET["name"] IS empty';
    //throw invalid request
    ...
}

and the browser prints $GET["name"] IS empty .

Answer 1

your deliver_response() function doesn't actually send the result to the browser. It just encodes the $response as JSON and stores it in $json_response .

Try adding an echo $json_response; to the end of that function.

And then, access your URL: http://localhost/Test8/?name=Java